PGDIR_SHIFT        26 arch/x86/include/asm/pgtable-2level_types.h #define PGDIR_SHIFT	22
PGDIR_SHIFT        32 arch/x86/include/asm/pgtable-3level_types.h #define PGDIR_SHIFT	30
PGDIR_SHIFT        28 arch/x86/include/asm/pgtable_64_types.h #define PGDIR_SHIFT	39